Transcript Patterns of Evolution

Patterns of Evolution
Honors Biology- Mr. Wilmot
MACROEVOLUTION/MICROEVO
LUTION
Macroevolution- One group of animals
evolves into another….due to large
scale changes that take place over long
periods of time.
●
Microevolution- Small scale changes
within a species to produce new
varieties or species in a relatively short
amount of time.
●
MACROEVOLUTION/MICROEVO
LUTION
Both involve changes in allele frequencies
in gene pools
●Both work through the same basic
processes
●The difference is largely one of approach
and scale
●Each offers different insights into the
evolution process
●
MACROEVOLUTION/MICROEVO
LUTION
MACROEVOLUTION/MICROEVO
LUTION
Dog Variability When bred
for certain traits, dogs become
different and distinctive. This is
a common example of
microevolution—changes in
size, shape, and color—or
minor genetic alterations. It is
not macroevolution: an upward,
beneficial increase in
complexity.
●
MACROEVOLUTION/MICROEVO
LUTION
Macroevolution has never been observed
in any breeding experiment.
●
●
PATTERNS OF
MACROEVOLUTION
These are models of evolution:
A. Mass Extinctions
B. Adaptive Radiation
C. Convergent Evolution
D. Coevolution
E. Gradualism
F. Punctuated Equilibrium
MASS EXTINCTIONS
●
Event in which many types of living things
became extinct at the same time.
●Huge numbers of species disappeared.
●Whole ecosystems were wiped out.
Resulted in burst of evolution of new species
in new habitat
●Disrupted energy flow throughout the
biosphere and caused food webs to collapse
●
MASS EXTINCTIONS
●
Possible causes
Asteroids hitting earth
●Volcanic eruptions
●Continental drift
●Sea levels changing
●
ADAPTIVE RADIATION
(DIVERGENT EVOLUTION)
The evolution of an ancestral species,
which was adapted to a particular way of
life, into many diverse species, each
adapted to a different habitat
●Many new species diversify from a
common ancestor .
●The branching out of a population
through variation.
●The new species live in different ways
than the original species did.
●
ADAPTIVE RADIATION
ADAPTIVE RADIATION
ADAPTIVE RADIATION
Diversity
in anoles
is most striking
in the Caribbean
islands
ADAPTIVE RADIATION
Hawaiian
honeycreepers
●Variation in
color and bill
shape is related
to their habitat
and diet
●
CONVERGENT EVOLUTION
Opposite of divergent evolution (adaptive
radiation)
●Unrelated organisms independently evolve
similarities when adapting to similar
environments, or ecological niches
●Analogous structures are a result of this process
●Example: penguin limb/whale flipper/fish fin
●The wings of insects, birds, pterosaurs, and bats
all serve the same function and are similar in
structure, but each evolved independently
●
CONVERGENT EVOLUTION
CONVERGENT EVOLUTION
CONVERGEN
T
EVOLUTION
CONVERGENT EVOLUTION
ocotillo (left) from the American Southwest, and in the allauidia (right)
from Madagascar
CONVERGENT EVOLUTION
Hummingbird Hawkmoth
CONVERGENT EVOLUTION
Similar body
shapes and
structures have
evolved in the
North
American
cacti...and in
the euphorbias
in Southern
Africa
COEVOLUTION
The mutual evolutionary influence between two
species
●When two species evolve in response to changes in
each other
●They are closely connected to one another by
ecological interactions (have a symbiotic
relationship) including:
●Predator/prey
●Parasite/host
●Plant/pollinator
●Each party exerts selective pressures on the other,
thereby affecting each others' evolution
●
COEVOLUTION
COEVOLUTION
A fly and an orchid--can influence
each other's evolution
COEVOLUTION
Bumblebees and the flowers the they pollinate
have co-evolved so that both have become
dependent on each other for survival.
COEVOLUTION
Coevolution between the
yucca moth and the yucca
plant. (right) A female
yucca moth pushing pollen into the stigma
tube of the yucca flower
while visiting the flower
to deposit her eggs.
Yucca moth larvae (left)
feeding on seeds in
the yucca fruit.
COEVOLUTION
Clown Fish and Sea anemone
COEVOLUTION
Praying Mantis simulates plant to protect itself
from predators and eats pests that are attracted to
and feed on the plant, so it protects the plant.
COEVOLUTION
Shrimp cleaning
Titan triggerfish
in Pacific Ocean
GRADUALISM
The evolution of new species by gradual
accumulation of small genetic changes
over long periods of time
●Emphasizing slow and steady change in
an organism
●Occurs at a slow but constant rate
●Over a short period of time it is hard to
notice
●
GRADUALISM
GRADUALISM
Current living zebras (top), extinct quaggas (bottom)
GRADUALISM
GRADUALISM
PUNCTUATED EQUILIBRIUM
Stable periods of no change (genetic
equilibrium) interrupted by rapid changes
involving many different lines of descent
●Opposite of gradualism
●It is rare, rapid events of branching
speciation
●Characterized by long periods of virtual
standstill ("equilibrium"), "punctuated" by
episodes of very fast development of new
forms
●
PUNCTUATED EQUILIBRIUM
Horseshoe crabs have change little since
their first appearance in the fossil record.
●They are in a state of equilibrium
●
PUNCTUATED EQUILIBRIUM
PUNCTUATED EQUILIBRIUM
PUNCTUATED EQUILIBRIUM
GRADUALISM OR
PUNCTUATED
EQUILIBRIUM
Patterns of Macroevolution
Flow Chart
Species
that are
Unrelated
form
in
Related
under
under
Interrelationships
Similar
environments
Intense
environmental
pressure
can undergo
can undergo
can undergo
Coevolution
Convergent
evolution
Extinction
in
Small
populations
in
Different
environments
can undergo
can undergo
Punctuated
equilibrium
Adaptive
radiation